Mechanical properties evaluation of PVC/plasticizers and PVC/thermoplastic polyurethane blends from extrusion processing

Mechanical and processing properties of blends of poly(vinyl chloride) (PVC) with di-isodecyl phthalate (DIDP) and thermoplastic polyurethane (TPU) were compared with di-2-ethylhexyl phthalate (DOP). The influence of processing conditions on the mechanical properties was studied by changing the content of the additives and using different twin screw speeds. The mechanical properties (tensile strength, modulus, and energy) of PVC/DIDP presented the same behaviour as PVC/DOP at all concentrations. The mechanical characteristics of PVC/DOP and PVC/DIDP show that these systems are probably affected by the speed of the twin screw. Polyurethane blends exhibit better structural properties compared to the other plasticizers. The twin screw speed exhibited no influence on the stress-strain property profile of the PVC/TPU blends. The results indicate a minor influence on the decrease of PVC properties when the plasticizer used is a TPU. (C) 2002 Elsevier Science Ltd. All rights reserved.